The company, which is the UK's biggest department store chain, said its clearance sales had had a record-breaking first day with sales of £31.7m.

Overall sales for the five week period were £645m.

John Lewis's managing director, Andy Street, said: "In an economic climate which continues to be volatile, to have achieved these results is testimony to the strength of the John Lewis brand and the commitment of all our partners to give outstanding service."

Total sales were up by 14.8%, higher than the like-for-like figure of 13% which compares sales for stores open for at least a year.

"That hour when we opened our clearance website, at 5 o'clock on Christmas Eve, was our single busiest day online, ever," Mr Street said.

"And when we opened our shops for clearance on the 27th, we had the best day of trade ever - so more proof that it's the two hand-in-glove. It's not one at the expense of the other.

"There's still a story about people wanting to go into department stores and have that experience of seeing things, touching and even tasting it in the outlets where we have food halls."

Record numbers of people visited UK retailers' websites on Boxing Day, information service Experian said last week.

There were 113 million visits to retailers' websites the day after Christmas, it said.

There is no indication yet whether those extra visits translated into higher sales, that will come when retailers publish their Christmas sales figures in the coming weeks.

They will give an indication of whether people spent more than they normally do, or are just changing their shopping habits.

Neil Saunders, managing director of the retail analysts Conlumino, said the John Lewis results were outstanding: "A stellar set of figures from John Lewis kicks off the trading update season and sets an extremely high bar that most other retailers will struggle to match.

"By any standards, this is an impressive performance, but when the general trading environment over Christmas is taken into account it underlines the fact that John Lewis is outperforming the market by a very significant degree."

2013 could be another tough year for the retail sector as a whole, analysts say.

Consumers are likely to remain cautious while the fate of the economy is still uncertain, said retail analysts at BDO in a recent report. But lower unemployment should ease the squeeze on household budgets that has been going on for the past two years, it said.

Others predict more of the same due to "shaky" consumer confidence.

"Austerity Britain is here to stay and 2013 will feel remarkably like 2012," said David McCorquodale, head of retail at KPMG, at the end of last year.

He thinks lack of growth will mean people put off buying more expensive items.